Robotics is the exciting intersection of a number of engineering fields including mechanical engineering, electrical engineering, and computer science. This project was designed as the basis for a two-day workshop for high school age students to introduce them to engineering principles and giving them a jumping off point for exploring their interests further. There is something for everyone here, even if it is just for the art it creates. The design goals were:

Easy to build.

Easy to program.

Did something interesting.

Low-cost so participants could take it home and continue to learn.

With those goals in mind, here were a couple of the design choices:

Arduino compatible for ease of programming.

4xAA battery power for cost and availability.

Stepper motors for accurate motion.

3D Printed for ease of customization.

Pen plotting with Turtle graphics for interesting output.

Open Source so you could make one of your own!

The pricing on this one is a bit confusing because I've broken it into parts depending on if you want to solder or have a 3D printer available. Basically what I'm offering:

Review Breakdown

Average Ratings

Great little bot for getting kids excited about robotics

There is something about a physical robot putting pen to paper that excites and stimulates young minds more than the prettiest graphics on a screen could ever do. Amazingly, there is a huge "hole" in the robotics market to serve this purpose. OSTR stands alone, but is by no means a compromise.

The electronics kit is straightforward and easy to assemble. The parts shipped are packaged correctly and the components chosen are easy to differentiate and assemble. The instructions on how to assemble them are also organized well and the order of assembly is correct for making sure that the parts are easy to solder (short components first, etc.). We have not used the IR wall detection yet, but this was a very nice touch which helps give the robot some additional educational opportunities.

The 3D printed body shipped is also very good quality. I was nervous at first because the holes for the metal nuts were not well shaped, but I found that pressing the nut into place by sticking the bolt through the hole, then threading the nut on to "pull" it into the plastic and finally removing the bolt, leaving the now-captured nut in place worked very well. The wheels also fit on to the motor shafts perfectly. I don't think that the "grub screw" method in the documentation would have worked at all with these wheels at all, but thankfully was unnecessary. The instructions also recommend threading the (long) motor and servo wires under the chassis but I found that this caused considerable interference with the movement of the pen.

The overall design of the robot is very well thought out -- putting the four AA batteries as low on the chassis as possible gives the robot a great low center of gravity and also adds considerable weight which helps the robot move around on the paper. The robot is pretty robust and other than it being stepped on or falling off of a table, I would not be worried about it being man-handled by excited children. I found that calibration was largely unnecessary, especially given that dead-reckoning movement is highly inaccurate to begin with. We were printing simple designs in only a few minutes. I think that adding a few washers to the caster so that it helps keep the robot from "rocking" would improve movement even more, but we really are talking about finicky little details.

There are only two "downsides" to OSTR, and neither prevents me from recommending this to anyone. The first is that you must connect a cable to the robot to program it. This is however easily solved with any of the BLE-to-UART modules that you can find online. The other downside is that for younger kids, programming the robot in Arduino's IDE is a little challenging. I am looking to see how difficult it would be to use any of the Blockly-inspired GUIs to program the robot with any tablet or computer.

OSTR really is a wonderful, relatively inexpensive Turtle Graphics robot. I would absolutely recommend it to anyone who would like a basic drawing robot platform.

(Please note that Tindie doesn't let me not rate the communication; I did not try to communicate with the business owner but could not mark this field "not applicable")

Robot is a great little project

Turtle Robot a good first tech project

The Turtle Robot is a good first tech project for anyone wanting to learn more about programming Arduinos, electronics, 3D printing, CAD and design. It gently guides you through each step to complete the project step by step. It also gives you enough information and access to modify the programming to explore further. If you have access to a 3D printer, I suggest you buy the kit minus the printed parts. Many libraries not have 3D printers you can use for free, including plastic. Check you local library.

The weak point on the robot is the wheel design. The spooks are thin and the center hole is a little too big making them loose. This is a perfect chance to also learn a little CAD by importing the files and modifying them for a better fit. I also drilled the stepper motor shafts and tapped them for a M3 screw where the wheel holes are. Putting the screw all the way through the motor shaft makes a very strong connection.

The link to code to test the LEDs in the documentation is missing. It would be nice if the code were put back on GitHub.

Response from MakersBox | May 24, 2018

Thanks for the review! I hope you'll consider uploading a photo in a comment on the Instructable page at https://www.instructables.com/id/OSTR/ or your favorite social media with the tag #TurtleRobot. I'd love to see how it turned out!

I agree about the wheels. I've uploaded a thicker wheel on the Thingiverse page at https://www.thingiverse.com/thing:2881396. Getting the hub right requires calibrating your printer, but the M3 screw works as well.

I've upload the firmware for testing the eyes, writing text, and making patterns to the Github at https://github.com/aspro648/OSTR/tree/master/firmware.

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